空调负荷的比例和影响日益增大,为分析其停机特性、启动特性以及电压扰动特性,选用一台辅助电热型分体落地式房间空调器进行实测。结果表明:0.6倍额定电压为空调的停机电压;空调启动时电流冲击倍数可达5~10倍,在0.3~0.5S之内平息;电压扰动过程中,当电压大于停机电压时有功功率变化小而无功功率变化大,当电压降到停机电压后空调停机且功率为0,当电压恢复到187V后再经过3~5s空调可重新启动,因此空调的电压扰动特性是分时段的。在此基础上对单台空调进行建模:电压高于停机电压时采用Karlsson-Hill模型,低于停机电压时空调停机,电压恢复时采用启动模型,可用一指数函数近似拟合功率振荡下降的包络线,结果表明该负荷模型可以很好地拟合空调的特性。
A separated - foot-mounting room air-conditioner with auxiliary electrical heater is tested to investigate its influence on power system stability, Its drop out characteristic, starting characteristic and response to voltage dips are analyzed. The test results show that, 0.6 p.u. voltage is the critical voltage for stalling, and the current impact can reach five to ten multiples of the normal when the air-conditioner starts and will come back within 0. 3 to 0.5 second, During the voltage disturbance, when voltage is above the stalling voltage, the active power changes little while the reactive power changes greatly; when voltage drops to the stalling voltage, the air -conditioner stalls with power being zero; when voltage is restored to over 187 V, the air -conditioner can restart with time delay of 3-5 s. So its voltage disturbance characteristic is sectional. Accordingly, a model of single air conditioner is built up. When voltage is above 0.6 p. u. , the Karlsson-Hill model is suitable; when below, the air-conditioner stalls; when restored, a subsection model is constructed for starting, which uses an exponential function to fit the envelope of power oscillation. Result shows that the proposed model simulates the dynamic of air -conditioner well.